A siren is moving past Mary as she sits stuck in traffic to marry the pitch of the siren changes as it passes her position what causes this to happen

Initially, a particle is moving at 5.33 m/s at an angle of 37.9° above the horizontal. two seconds later, its velocity is 6.11 m/s at an angle of 54.2° below the horizontal. what was the particle's average acceleration during these 2.00 seconds in the x-direction (enter first) and the y-direction?

Which situation will produce the greatest change of momentum

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up